JP-A-2011-112938 describes a technique, in printing a plurality of copy units, which sets a waiting period from print completion of a predetermined number of copy units to a print start of a subsequent copy unit. Since this technique sets the waiting period according to a time required for a post-processing (sorting or clipping) of a user for a printed sheets, convenience of printing can be improved.
However, this technique does not consider a possibility that a user interrupts the printing, for example, when the printing is performed differently from an intention of the user. Therefore, when the user interrupts the printing, this technique may be inconvenient.